Consumers are dissatisfied with their cleaner's ability to prevent soils, such as soap scum, toothpaste, hard water, greasy soils, brake dust, grime, rust, and toilet ring, from building up on household surfaces and articles. Specifically, consumers want surfaces to maintain their cleaned look for longer periods of time.
One approach to solving this problem entails applying a sacrificial layer of material which is dissolvable by water with the attendant removal of dirt. Suitable cleaning formulations must be carefully applied in order to create a sufficiently thick, dry sacrificial film. Unfortunately, inconsistent consumer cleaning habits make this an almost impossible task. In many cases, the surface is rinsed before the film is dried thereby creating a sacrificial coating that is too thin to prevent soils from adhering. In cases where the sacrificial coating is too thick, an unsightly macroscopic film with visible residue is created.
U.S. Pat. No. 6,331,517 to Durbut describes an aqueous glass cleaning composition comprising an anionic surfactant and a hydrophilic, anionic maleic acid-olefin copolymer. The surface becomes hydrophilic such that the initial contact angle of water on the treated surface is from 12 to 23 degrees. While the presence of the copolymer yields an efficient hydrophilic surface coating, this sacrificial coating is easily rinsed away unless it is very thick. U.S. Pat. No. 6,242,046 to Nakane et al. describes a more permanent stain-proofing treatment that employs a non-water soluble resin and a metal oxide sol. With this treatment, the surface must be washed with water before the film dries on the surface. This step appears to homogeneously spread a stainproof-treating agent on the surface and removes excess stainproof-treating agents. When washing with water is not done properly, however, the excess causes surface nonuniformity. WO 00/77143 to Sherry et al. describes a surface substantive polymer which purportedly renders treated surfaces hydrophilic. The preferred polymers include a copolymer of N-vinylimidazole N-vinylpyrrolidone (PVPVI), a quaternized vinyl pyrrolidone/dialkylaminoalkyl acrylate or methacrylate copolymer, or a polyvinylpyridine-N-oxide homopolymer. These polymers are purported to modify the surface to achieve water to treated surface contact angles of less than 50 degrees.
U.S. Pat. No. 6,251,849 to Jeschke et al. describes a cleaner for easier next time cleaning that contains a cationic polymer comprising at least 40 mole percent of a quaternary monomer such as methacrylamidopropyl trimethylammonium chloride. The cleaning performance is said to improve with the presence of these polymers in the cleaner but it is expected that the wetting properties will decline after a single rinse step.
A second approach to preventing soil buildup is to deposit a release aid on the treated surface to modify surface characteristics. Unfortunately, the application of cleaner or water causes the soluble release aid to be completely removed. WO 02/18531 to Ashcroft et al. describes the use of cleaning solutions containing antioxidants that function as soil release agents. The antioxidants are purportedly retained on the surface so that soil subsequently deposited thereon is prevented from polymerizing thereby allowing for easier removal. However, it is expected that the antioxidants will not be effective on all soil types. WO 00/29538 to Baker et al. describes a non-greasy sacrificial coating containing cellulose or gum and a release aid, such as lecithin. While this coating prevents sticking, its visual appearance makes it unsuitable for glass, counter-tops, showers and the like.
In view of the deficiencies of past endeavors in developing cleaning compositions that leave satisfactory low maintenance treated surfaces, the art is in search of cleaning compositions that provide a thin, stable invisible film that facilitates removal of a variety of soils. The cleaning composition should be suitable for household surfaces and should be rapidly adsorbed on the surface to yield a uniform film that causes water to sheet off and oil to roll off.